jdk/jshell/CommandCompletionTest.java fails "CommandCompletionTest.testSave" test case

The following test failed in the JDK21 CI:

jdk/jshell/CommandCompletionTest.java

Here's a snippet from the log file:

----------System.out:(76/4230)----------
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testClassPath(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testClassPathWithSpace(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testCommand(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testDrop(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testEdit(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testEnv(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testHelp(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testHistory(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testList(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testOpen(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testReload(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testReset(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testSave(): failure
java.lang.AssertionError: Expected empty user error output, got: Exception in thread "main" expected [true] but found [false]
at org.testng.Assert.fail(Assert.java:99)
at org.testng.Assert.failNotEquals(Assert.java:1037)
at org.testng.Assert.assertTrue(Assert.java:45)
at ReplToolTesting.testRawCheck(ReplToolTesting.java:343)
at ReplToolTesting.testRaw(ReplToolTesting.java:308)
at ReplToolTesting.test(ReplToolTesting.java:259)
at ReplToolTesting.test(ReplToolTesting.java:246)
at ReplToolTesting.testNoStartUp(ReplToolTesting.java:242)
at CommandCompletionTest.testSave(CommandCompletionTest.java:295)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:132)
at org.testng.internal.TestInvoker.invokeMethod(TestInvoker.java:599)
at org.testng.internal.TestInvoker.invokeTestMethod(TestInvoker.java:174)
at org.testng.internal.MethodRunner.runInSequence(MethodRunner.java:46)
at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:822)
at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:147)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
at org.testng.TestRunner.privateRun(TestRunner.java:764)
at org.testng.TestRunner.run(TestRunner.java:585)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:384)
at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:378)
at org.testng.SuiteRunner.privateRun(SuiteRunner.java:337)
at org.testng.SuiteRunner.run(SuiteRunner.java:286)
at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)
at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)
at org.testng.TestNG.runSuitesSequentially(TestNG.java:1218)
at org.testng.TestNG.runSuitesLocally(TestNG.java:1140)
at org.testng.TestNG.runSuites(TestNG.java:1069)
at org.testng.TestNG.run(TestNG.java:1037)
at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:93)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
at java.base/java.lang.Thread.run(Thread.java:1623)
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testSet(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testUserHome(): success
config ReplToolTesting.setUp(): success
test CommandCompletionTest.testVarsMethodsTypes(): success

===============================================
jdk/jshell/CommandCompletionTest.java
Total tests run: 16, Passes: 15, Failures: 1, Skips: 0
===============================================

----------System.err:(10/538)----------
java.lang.Exception: failures: 1
at com.sun.javatest.regtest.agent.TestNGRunner.main(TestNGRunner.java:95)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
at java.base/java.lang.Thread.run(Thread.java:1623)

JavaTest Message: Test threw exception: java.lang.Exception
JavaTest Message: shutting down test

result: Failed. Execution failed: `main' threw exception: java.lang.Exception: failures: 1

Normally a Tier1 failure would start at P2, but this failure is intermittent
so I'm starting it at P3.